Understanding Humidity and Its Impact on Hardwood Floors

Hardwood floors are an enduring choice for homeowners across the Puget Sound, celebrated for their natural beauty, warmth, and timeless appeal. They add significant value and character to any home, from classic Seattle bungalows to modern Bellevue estates. However, as a natural material, wood is inherently responsive to its environment, particularly to moisture in the air. For those of us living in a region known for its varying weather patterns, understanding humidity and its impact on hardwood floors is not just beneficial—it’s essential for preserving your investment and ensuring the longevity of your beautiful flooring. At Carpet To Go in Bellevue, WA, we help our clients understand the nuances of hardwood floor humidity impact and how to effectively manage it.

The Hygroscopic Nature of Wood

Wood is a hygroscopic material, meaning it constantly absorbs and releases moisture from the surrounding air until it reaches equilibrium. This natural process causes wood to expand when it absorbs moisture (in high humidity) and contract when it releases moisture (in low humidity). While some movement is normal and expected, extreme or rapid fluctuations in humidity can lead to a range of issues, impacting both the structural integrity and aesthetic appeal of your hardwood floors.

How High Humidity Affects Hardwood Floors

The Puget Sound region, with its often damp climate, can present challenges for hardwood. When relative humidity (RH) levels in your home climb too high, your hardwood planks will absorb excess moisture.

• Swelling and Expansion: As wood fibers take on water, the planks will swell. If there isn’t enough space for this expansion (e.g., proper expansion gaps weren’t left during installation), the planks will push against each other.
• Cupping: This is perhaps the most common sign of high humidity. The edges of the planks swell and rise higher than the center, creating a concave or “cupped” appearance across the width of the board. This happens when the top surface dries out more quickly or is exposed to less moisture than the underside.
• Crowning: Less common but also possible, crowning is the opposite of cupping, where the center of the plank is higher than the edges. This can occur if the top surface absorbs more moisture than the bottom, or after a floor has been sanded while it was cupped, and then later dries out.
• Buckling: In extreme cases of moisture absorption and expansion, the planks can lift entirely from the subfloor, creating large “humps” or waves in the floor. This is a severe form of damage requiring professional intervention.
• Mold and Mildew: Persistent high humidity also creates an ideal environment for mold and mildew growth, not just on the surface but underneath the planks, potentially leading to unhealthy indoor air quality and structural damage.

How Low Humidity Affects Hardwood Floors

While high humidity is a concern, excessively dry conditions can be equally damaging, especially during colder months when heating systems strip moisture from the air.

• Shrinking and Contraction: When wood releases moisture, the planks will contract.
• Gaps Between Planks: As planks shrink, unsightly gaps can appear between them. While minor gapping in winter is normal, excessive gapping indicates very dry conditions.
• Cracking and Splitting: Prolonged periods of extreme dryness can lead to the wood becoming brittle, resulting in cracks, splits, or even splintering of the planks.
• Squeaking: Loose boards due to contraction can also lead to increased squeaking as you walk across the floor.

The Ideal Humidity Range for Hardwood Floors

To maintain the health and beauty of your hardwood floors, it’s crucial to keep your indoor relative humidity within a stable range, typically between 35% and 55%. Temperatures should generally be maintained between 60°F and 80°F. Consistent conditions minimize the natural expansion and contraction of wood, preventing stress on the planks and preserving their appearance.

Strategies for Hardwood Floor Moisture Control in the Puget Sound

Given the unique climate of the Puget Sound, proactive hardwood floor moisture control is key.

1. Monitor Indoor Humidity: Invest in a hygrometer (a simple device that measures humidity) for different areas of your home. This allows you to track levels and take action when needed.
2. Utilize HVAC Systems:
   • Air Conditioning in Summer: Your AC system not only cools your home but also removes moisture from the air, acting as a natural dehumidifier.
   • Dehumidifiers: In damp areas like basements or during particularly humid periods, a standalone dehumidifier can effectively pull excess moisture from the air.
   • Humidifiers in Winter: When heating systems dry out the air, a humidifier can add much-needed moisture back into your home, preventing excessive shrinking and gapping. Consider a whole-house humidifier for consistent results.
3. Ensure Proper Ventilation: Use exhaust fans in kitchens and bathrooms when showering or cooking to vent moisture outside. Ensure good airflow throughout your home by occasionally opening windows on dry days.
4. Manage Spills and Moisture Sources: Promptly wipe up any spills on your hardwood. Avoid over-wet mopping. Place mats at entryways to absorb tracked-in rain or snow. For potted plants, use trays with risers to prevent moisture accumulation beneath them.
5. Acclimatization Before Installation: If you’re installing new hardwood, ensure the planks are properly acclimated to your home’s environment before installation. This typically involves letting the wood sit in the room for several days or weeks to adjust to the temperature and humidity. Our professionals at Carpet To Go always ensure proper acclimatization for optimal results.
6. Proper Installation: A professional installation that leaves appropriate expansion gaps around the perimeter of the room is critical to accommodate wood’s natural movement.

Protect Your Investment with Carpet To Go

Your hardwood floors are a significant investment and a beautiful asset to your home. By understanding humidity and its impact on hardwood floors and implementing effective hardwood floor moisture control strategies, you can prevent common problems like cupping, gapping, and cracking, ensuring your floors remain stunning for decades to come. Don’t let the unique Puget Sound climate diminish the beauty of your hardwood.

Contact us and check out our showroom location in Bellevue, WA, or call for an In-Home Consultation with a Design Consultant. Carpet To Go serves homeowners, contractors, realtors, businesses, and individuals with a friendly, knowledgeable, and caring staff of professionals.